BACKGROUND: There are two kinds of cannulated screws (single- and double-headed) In clinic. Common single-headed cannulated compression screw is easy to cause shortened femoral neck, and screw dropping occurs usually when osteoporosis; thereafter, choosing single- or two-headed cannulated compression screw in the treatment of femoral neck fracture remains controversial. OBJECTIVE: To investigate the biomechanical effects of two double-headed and ordinary (single-headed) cannulated compression screws and different spatial configurations in the treatment of femoral neck fractures by finite element analysis. METHODS: The original DICOM data were obtained by collecting a thin layer CT scan of the proximal femur of a healthy adult volunteer (male, 30 years old). The proximal femoral model was established in MIMICS10.01 software. The model was imported into the UG 8.0 software to establish the femur neck fracture model (Pauwels angle 60°). A three-dimensional model of double-headed and ordinary cannulated compression screw was obtained by three-dimensional scanning modeling. In the UG 8.0 software, the femoral neck fracture assembly modeling was performed according to the horizontal and vertical distribution of two screws. The established model was introduced into the ANSYS 14.5 software to calculate the opening angle of the femoral neck fracture, the relative displacement of the fracture end and the stress distribution. RESULTS AND CONCLUSION: (1) In terms of biomechanical stability: The opening angle and displacement of the fracture end in the two screws in the horizontal position group were smaller than those in the vertical position group. The opening angle and displacement of the double-headed cannulated compression screw group were smaller than those in the ordinary cannulated compression screw. (2) Stress distribution: The stress distribution of the two screws was different. The stress distribution on the screw in the double-headed group was more dispersed than that in the ordinary group, and some stress was transmitted to the tail of the screw. In the ordinary group, the stress on the screw was mainly concentrated on the fracture end. There was also a difference in the stress distribution between horizontal and vertical position groups. When the two screws were horizontally fixed, the stress distribution on the front screw was more concentrated, while the vertical position was mainly concentrated on the upper one. (3) These results imply that the double-headed cannulated compression screw is more stable and reliable than the ordinary cannulated compression screw in the treatment of femoral neck fracture. The horizontal fixation of the two screws has better biomechanical stability than the vertical fixation. Therefore, the clinical application of double-head compression screws can be used to treat femoral neck fractures. When two screws are selected, horizontal fixation should be used.

Background Nitrosamines (NAms) are highly carcinogenic and frequently detected in drinking water systems in China, indicating potential human health risk through drinking water. Objective To analyze the distribution of NAms in drinking water in Shanghai and to evaluate relevant human health risk. Methods A total of 94 samples of source water and 120 samples of finished water were collected in February (dry period) and August (wet period) of 2021 from 30 drinking water plants in Shanghai, and eight NAms were quantitatively analyzed by gas chromatography tandem mass spectrometry after solid phase extraction. Cancer risks for different age groups caused by NAms exposure through water were evaluated using Monte Carlo probabilistic method and carcinogens risk assessment model recommended by the United States Environmental Protection Agency. Results The concentrations of total NAms in source and finished water were 12.56-65.86 ng·L⁻¹ and 8.52-57.38 ng·L⁻¹, respectively. The average concentration of total NAms was higher in source water (33.50 ng·L⁻¹) than in finished water (22.07 ng·L⁻¹, P<0.05) during dry season, and lower in source water (16.90 ng·L⁻¹) than in finished water (21.02 ng·L⁻¹, P<0.05) during wet season. The average concentration of total NAms in source water during dry season was twice of that during wet season. The positive rate of N-nitrosodimethylamine (NDMA) was the highest (100%) among the eight NAms. The cancer risk of exposure to NAms in finished water in Shanghai was mainly from the ingestion route, which was mostly caused by NDMA. The cancer risk from exposure to NAms in water for children (median=4.32×10⁻⁵) was slightly higher than that for adults (median=3.34×10⁻⁵) and adolescents (median=2.27×10⁻⁵). The cancer risks of exposure to NAms in water for people of different ages were mainly (80% - 95%) at an acceptable level (1×10⁻⁶ - 1×10⁻⁴). Conclusion NAms contamination is positive in Shanghai’s drinking water and NDMA is the main contaminant. The removal of NAms in water by current water treatment process is season-dependent. The cancer risk of children exposed to NAms in water was slightly higher than that of adults and adolescents, but all at acceptable levels.

Objective:To explore the predictive value of serum thyroglobulin autoantibody (TgAb) for recurrence / metastasisin of thyroglobulin (TG)-negative and TgAb-positive patients with differentiated thyroid carcinoma(DTC) after thyroid ablation.Methods:The clinical data of 57 patients with DTC,undergoing complete resection of thyroid tissue,TG negative and TgAb positive,who were reviewed in Liaocheng People's Hospital during April 2013 to April 2015,were selected and divided into recurrence/metastasis group (n=20) and no recurrence/metastasis group (n=37).The TG and TgAb levels in the two groups were detected and compared by the electrochemical luminescence method,the sensitivity,specificity,positive predictive value and negative predictive value of TgAb in the diagnosis of DTC recurrence / metastasis were analyzed;the independent risk factors of DTC recurrence / metastasis were analyzed by Logistic regression.Results:The TgAb levels(72～3850 IU/mL) in the recurrence/metastasis group was higher than that(18～3638 IU/mL) in the no recurrence/metastasis group,the difference was statistically significant (P＜0.05).The sensitivity,specificity,positive predictive value,negative preictive value of TgAb in the diagnosis of recurrence/metastasis of DTC were 85.71％,83.33％,75.00％,90.91％,respectively.Logistic Regression analysis showed that the 100≤ TgAb ＜204 IU/mL,204≤ TgAb≤ 1000IU/mL,and ＞ 1000IU/rnL levels of TgAb were the independent risk factors of rucurrence/metastasis ofDTC (OR=1.267,2.853,6.791,P＜0.05).Conclusion:TgAb can be used as evaluation of an important index of the recurrence/metastasis of patients with DTC when serum thyroglobulin (TG) was negative and TgAb was positive after thyroid ablation.The higher the TgAb levels,the more probability of the recurrence/metastasis.

Objective:To investigate the early clinical outcomes of a minimally invasive anterolateral approach (Orthopadische chirurgie munchen, OCM) versus a conventional (posterolateral approach, PLA) hemiarthroplasty in the treatment of senior femoral neck fractures.Methods:A retrospective analysis was performed on 90 elderly patients with femoral neck fractures who received anterolateral and posterolateral approaches for hemiarthroplasty in the Second Affiliated Hospital of Soochow University from December 2019 to June 2021 and were followed up. In the OCM group, there were 45 cases, including 18 males and 27 females, aged 83.33±5.29 years (range, 76-96 years); In the PLA group, there were 45 cases, including 13 males and 32 females, aged 81.87±5.00 years (range, 75-94 years). Postoperative, surgical indices, perioperative bleeding, and soft tissue injury were assessed; pain was assessed using the visual analogue scale (VAS), and hip function was evaluated using the Harris score and the University of California at Los Angeles (UCLA) score.Results:The incision length, postoperative hospital stay, hemoglobin reduction, and occult blood loss were lower in the OCM group than in the PLA group ( P<0.05), but there was no significant difference in intraoperative bleeding and postoperative transfusion rate ( P>0.05). Serum creatine kinase and C-reactive protein levels (232.98±83.70 IU/L and 81.67±48.85 mg/L) were lower in the OCM group than in the PLA group (296.93±124.58 IU/L and 104.79±36.75 mg/L) 1 day after surgery, and the differences were statistically significant ( t=2.86, P=0.005; t=2.54, P=0.013). Postoperative pain was significantly improved in all patients, and VAS scores were lower in the OCM group than in the PLA group at 12 h, 24 h, and 48 h postoperatively ( P<0.05). The time to get out of bed after surgery was 20.73±4.99 h in the OCM group compared with 41.69±13.58 h in the PLA group, with a statistically significant difference ( t=9.71, P<0.001). Harris scores (63.31±6.21 and 75.76±4.91) and UCLA scores (1.84±0.42 and 3.69±0.76) were higher in the OCM group on the day of discharge and at 1 month postoperatively than in the PLA group (52.69±10.01 and 71.33±3.66); (1.62±0.54 and 3.16±0.80) points, all with statistically significant differences ( P<0.05). However, the differences in Harris score and UCLA score between the two groups at 6 months postoperatively were not statistically significant ( P>0.05). There were two cases of intermuscular vein thrombosis in the OCM group, with a complication rate of 4% (2/45), and one case of dislocation in the PLA group, with a complication rate of 2% (1/45), there was no significant difference between the two groups ( P=1.000). Conclusion:The minimally invasive anterolateral approach is a more ideal procedure for elderly patients with femoral neck fractures undergoing hemiarthroplasty. It has the advantages of a short incision, small soft tissue damage, low occult blood loss, early removal from bed, a short postoperative hospital stay, an improvement in pain, and a good early recovery of hip function.

Objective:To investigate the application effect of 3D digital modeling combined with 3D printed model in assisting the classroom theoretical teaching of orthopedics in five-year undergraduate students majoring in clinical medicine.Methods:In May 2022, 33 five-year undergraduate students majoring in clinical medicine in the class of 2018 in Southwest Medical University were selected and divided into experimental group with 17 students and control group with 16 students according to the odd or even student number. The students in the experimental group were taught by traditional PPT+3D digital modeling combined with 3D printed model, and those in the control group were taught by the traditional PPT teaching method. The teaching effect was evaluated by theoretical examination and a questionnaire survey on the degree of satisfaction with teaching. SPSS 25.0 was used to perform the t-test, the Mann-Whitney U test, the rank sum test, and the chi-square test. Results:The experimental group had a significantly higher score of theoretical examination than the control group (86.24±4.16 vs. 82.50±6.06). The questionnaire survey on the degree of satisfaction with teaching showed that compared with the control group, the experimental group had a significantly higher degree of satisfaction with the understanding and learning of orthopedic diseases [3 (2, 3) vs. 2 (2, 2), P < 0.05], the improvement in learning interest [2 (2, 3) vs. 2 (1, 2), P < 0.05], classroom innovation [3 (3, 3) vs. 2 (1.5, 2), P < 0.05], and overall classroom teaching [3 (2, 3) vs. 2 (2, 2), P < 0.05]. Conclusion:In assisting the classroom theoretical teaching of orthopedics in undergraduate students majoring in clinical medicine, 3D digital modeling combined with 3D printed model can provide concrete 3D models, reduce the difficulties in learning, improve the awareness of orthopedic diseases, strengthen learning interest, and increase the degree of satisfaction with teaching and academic scores.

Background Nitrosamines, especially N-nitrosodimethylamine (NDMA), are highly carcinogenic and frequently detected in drinking water systems in China, indicating potential human health risk through drinking water. Objective This study aims to analyze the distribution of NDMA in urban drinking water around China and to evaluate relevant human health risk, thus providing recommendations for drinking water safety standards. Methods The database of China National Knowledge Infrastructure was searched using nitrosamines and drinking water as key words in Chinese, and PubMed was searched usingN-nitrosodimethylamine or nitrosodimethylamine or NDMA, drinking water, and China as key words in English for relevant literature published from January 1, 2000 to March 1, 2021. Eligible data were extracted to statistically analyze the spatiotemporal exposure levels of NDMA in raw and finished water serving Chinese cities. According to the health risk assessment model for carcinogens recommended by the United States Environmental Protection Agency (US EPA), the cancer risk via drinking water of NDMA in finished water was evaluated for different age groups and different regions. Results A total of 102 studies were retrieved, 21 of which met the inclusion criteria and were finally included. The NDMA concentrations in 347 raw water samples and 276 finished water samples were extracted and studied, with positive rates of 82.4% and 67.0%, levels of not detected (ND)-141 and ND-67.1 ng·L⁻¹, and the 95th quantiles of 51.4 and 32.1 ng·L⁻¹, respectively. The level of NDMA in raw water was higher than that in finished water in cities of East and North China (P<0.05). East China had the highest average concentrations of NDMA in raw and finished water (21.4 and 9.0 ng·L⁻¹ respectively). In East China, the average concentrations of NDMA in raw and finished water from 2018 to 2019 (5.9 and 6.1 ng·L⁻¹ respectively) were significantly lower than those from 2015 to 2017 (28.7 and 16.5 ng·L⁻¹ respectively) (P<0.05). The average concentration of NDMA in rivers, lakes, ponds, and streams as drinking water sources (20.8 ng·L⁻¹) was significantly higher than that in groundwater sources (8.0 ng·L⁻¹) and in reservoir sources (6.5 ng·L⁻¹) (P<0.05). The average concentration of NDMA in finished water with pre-chlorination (9.4 ng·L⁻¹) was higher than that without (6.0 ng·L⁻¹) (P<0.05). The cancer risk of NDMA through drinking water for children over 1 year old in China decreased with older age, and the risk of infants aged 1~<2 years (2.52×10⁻⁴) was 23 times higher than that of adults (1.09×10⁻⁵) (P<0.05). Conclusion Raw water pollution is the main source of NDMA in urban drinking water in China, and current water treatment technology can partially remove NDMA. The NDMA level in finished water of East China shows a downward trend in recent two years. The carcinogenic risk of NDMA via drinking water for children is higher than that for adults, and their health risk management needs to be strengthened. The study findings recommend 35 ng·L⁻¹ as the limit of NDMA water quality safety standard in China.

OBJECTIVETo identify the patterns of airway collapse in patients with obstructive sleep apnea hypopnea syndrome(OSAHS) by dexmedetomidine induced sleep endoscopy.

METHODSForty-five obstructive sleep apnea patients diagnosed by polysomnography were given dexmedetomidine intravenously. Once the patient was sedated in dorsal position, the electronic nasopharyngoscope was inserted transnasally and positioned on five levels of the upper airway sequentially (velum, oropharyngeal lateral wall, tongue base, epiglottis and larynx) to observe and document the collapse. Each level should be observed no less than three apneas. The degree of airway narrowing was calculated by using the ImageTool. No obstruction was defined when the degree of airway narrowing <50%, and complete obstruction when ≥ 75%.

RESULTSIn 45 patients with OSAHS, 1 case showed no obstruction on any level, 6 cases demonstrated obstructions on single level only, and 38 cases demonstrated complete obstructions on multilevel, including 17 cases with complete obstructions on two levels, 15 cases complete obstructions on three levels, and 6 cases complete obstructions on four levels. The patterns of collapse found in the trial were: (1) circumferential stricture by velum collapse was found in 43 patients, and 41 cases showed complete obstructions; (2) the side wall of oropharynx all collapsed in a lateral configuration, and 32 cases showed complete obstructions on this level; (3) anteroposterior swallowing tongue base was common, 11 cases showed partial obstructions on level of tongue base, and 10 cases complete; (4) epiglottic collapses occurred in lateral configuration folding as V shape; in anteroposterior configuration, epiglottis met posterior wall of the pharynx due to swallowing tongue base; the server soften epiglottis obstructed the entrance of the larynx, while the mild soften epiglottis and the collapsed side wall of pharynx came into being obstructions in concentric configuration; (5) the arytenoid area and aryepiglottic fold mucosa inwardly covered the glottis when the obstruction occurred in the larynx.

CONCLUSIONSThe patterns of hypopharynx obstructions in OSAHS patients are multifarious. Lateral oropharyngeal wall, epiglottic and tone base collapse play an important role in the obstructions. The laryngeal obstruction can also be observed.

Adult ; Airway Obstruction ; pathology ; Endoscopy ; methods ; Female ; Humans ; Male ; Middle Aged ; Sleep ; drug effects ; Sleep Apnea, Obstructive ; pathology

OBJECTIVETo understand the current status of the disease burden of liver cancer in Jinchang cohort.

METHODSAll the liver cancer death data from 2001 to 2013 and medical records of liver cancer cases from 2001 to 2010 in Jinchang cohort were collected for the analyses of the mortality, standardized mortality, potential years of life lost (PYLL) and working PYLL (WPYLL) associated with liver cancer. Spearman correlation and the average growth rate were used to analyze the trends.

RESULTSA total of 207 liver cancer deaths occurred in Jinchang cohort from 2001 to 2013, accounting for 16.68% of total cancer deaths. There were 259 liver cancer inpatients, accounting for 6.79% of the total cancer cases inpatients, in which 83 died (32.05%). Liver cancer death mainly occurred in males, accounting for 88.89%, and the liver cancer deaths in females accounted for 11.11%. The standardized mortality rate was 42.32/100,000 in males and 15.31/100,000 in females. The growth rate of liver cancer mortality was 5.62% from 2001 to 2013. Liver cancer deaths mainly occurred in age groups 60-69 years (26.57%) and 50-59 years (24.15%). The PYLL was 2906.76 person-years, the average PYLL was 14.04 years. The WPYLL was 1477.00 person-years and the average WPYLL was 7.14 years. The direct economic burden of liver cancer was 6270.78 Yuan per person, 301.75 Yuan per day. The average stay of hospitalization was 21.32 days.

CONCLUSIONThe mortality rate of liver cancer is increasing and the disease burden is still heavy.

Aged ; China ; epidemiology ; Cohort Studies ; Cost of Illness ; Female ; Hospitalization ; economics ; statistics & numerical data ; Humans ; Liver Neoplasms ; economics ; mortality ; Male ; Middle Aged